Latest Dealer ECM flash - warm start high idle
Thread Starter
Senior Member
Joined: Aug 2016
Posts: 274
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From: Great White North
Polar White C43 Sedan
Latest Dealer ECM flash - warm start high idle
So in getting my annual service done there was an ECM flash that the dealer did.
Now when the car is warm, when starting most of the time it does a high idle run for a similar amount of time it used to do only when doing a cold start.
Anybody else experience this and does this sound right?
Now when the car is warm, when starting most of the time it does a high idle run for a similar amount of time it used to do only when doing a cold start.
Anybody else experience this and does this sound right?
Thread Starter
Senior Member
Joined: Aug 2016
Posts: 274
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From: Great White North
Polar White C43 Sedan
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From: Massachusetts
2018 C43 AMG Brilliant Blue Metallic
So in getting my annual service done there was an ECM flash that the dealer did.
Now when the car is warm, when starting most of the time it does a high idle run for a similar amount of time it used to do only when doing a cold start.
Anybody else experience this and does this sound right?
Now when the car is warm, when starting most of the time it does a high idle run for a similar amount of time it used to do only when doing a cold start.
Anybody else experience this and does this sound right?
Did you ask them to flash it or did they do it without you asking ?
Thread Starter
Senior Member
Joined: Aug 2016
Posts: 274
Likes: 37
From: Great White North
Polar White C43 Sedan
While I Like the bark when it starts, it takes quite a while for the idle to settle down just like if the engine was stone cold.
I'll query the dealer next time I'm around there.
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MBWorld Fanatic!
Joined: Mar 2017
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From: Omaha, NE
'16 AMG GTS, '21 AMG GLE53
It's a 2017 and it was apparently listed in their system as needing the SW update (I think it did other things as well as my bluetooth seems to connect to my phone quicker) so they did it as part of the B Service.
While I Like the bark when it starts, it takes quite a while for the idle to settle down just like if the engine was stone cold.
I'll query the dealer next time I'm around there.
While I Like the bark when it starts, it takes quite a while for the idle to settle down just like if the engine was stone cold.
I'll query the dealer next time I'm around there.
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Thread Starter
Senior Member
Joined: Aug 2016
Posts: 274
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From: Great White North
Polar White C43 Sedan
I had mine in yesterday for airbag recall, rattle fixes and the trim piece where the center console button is was delaminating. They stated they did a fuel system software update that was recommended and I'm now seeing this as well. I don't see how the slightly higher start-up RPM could be an issue, so long as the RPMs eventually run back down to normal idle. Nothing to worry about in my book.
So what I'm doing is waiting for it to settle down first but that of course means waiting around while it decides what it's doing.
I'm just curious why it needs to do it at all, it's essentially emulating a cold start but that's not necessary when everything is already toasty warm.
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Joined: Mar 2007
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From: NS, Canada
2023 E53 AMG, 2024 EQE AMG SUV
Experiencing the exact same thing here. Dealer says its normal even though it wasn't doing it prior to the update. Also lost the shift UP indicator in manual mode. Only the color indicators remain.
Senior Member
Joined: Nov 2017
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C43 AMG Coupe
They still haven't fixed that huh? Lost my "UP" thing probably 9 months ago now.
Senior Member
Joined: Mar 2007
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From: NS, Canada
2023 E53 AMG, 2024 EQE AMG SUV
I'm hoping with persistence they'll address it. It's going back this week for some other stuff. I've also noticed boost is very inconsistent after it "cold" starts again. I don't believe this latest software update is completely bug free.
Newbie
Joined: Nov 2016
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GLK 350
Greetings. I just got the flash as well.
After the 30 minute drive back to work, I scrolled through to check my mileage.
NO MPG calculations. Not on trip. Not on Effeciency (?) graph.
Back to dealership through 30 minutes of Christmas shopping traffic craziness.
After the 30 minute drive back to work, I scrolled through to check my mileage.
NO MPG calculations. Not on trip. Not on Effeciency (?) graph.
Back to dealership through 30 minutes of Christmas shopping traffic craziness.
Member
Joined: Dec 2016
Posts: 116
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'17 C43 Coupe
I had mine updated on Tuesday. Now when I start the car in Sports+, the exhaust crackles and pops 3-4 times (sounds amazing). I lost my tune so I'll have to redo that but it's solid for now. I also noticed that the car stays in high RPMs for MUCH longer in Sports+ with the update. I used to do a ton of highway driving in that mode and it was always "comfortable". Now it's impossible to drive in that mode without manually shifting or dealing with really high RPMs (not complaining, just a change I noticed).
Junior Member
Joined: Apr 2021
Posts: 45
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From: Canada
2017 C43 AMG
I brought my car in for B service and yeah noticed the same thing.. Its weird why the update would make it start like cold? I wonder why they did that, or if its a glitch in the update?
Junior Member
Joined: Nov 2020
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2017 AMG C43
I have noticed the higher idle as well. I have a 2017, took it to the dealership a few weeks back. They flashed my ecu with an update even though I was there to get the adaptation reset/adjusted on the tcu. I really don't mind it.
MBWorld God!
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I read a thread that talks about a similar problem: https://mbworld.org/forums/c450-c43-...r-updates.html
Had this exact same problem, although mine triggered after a TCU update (unless they updated something else as well and didn't note it down on the work order) since a year and a half ago. Notice all the 2019 does it so I guess that is intended behaviour. My dealership also said it was normal just like everyone else. Cold start is mostly meant to heat up the cats so I guess MB created the update to force a cold start due to regulations. However, I am not aware that other brands do this.
Had this exact same problem, although mine triggered after a TCU update (unless they updated something else as well and didn't note it down on the work order) since a year and a half ago. Notice all the 2019 does it so I guess that is intended behaviour. My dealership also said it was normal just like everyone else. Cold start is mostly meant to heat up the cats so I guess MB created the update to force a cold start due to regulations. However, I am not aware that other brands do this.
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Joined: Nov 2010
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Carrera Conv., E550, Mode3
SL550. High RPM when starting cold engine
I just had my 2017 SL550 with 11K miles at the dealership for update. Idle is very similar during warm startups as well as cold start ups. We also own a 2014 E550 with 38K miles that only has the fast idle during cold starts! I asked the dealer to explain the difference, and was told the starting with 2017 the injection system in the 4.7 motor is very similar to a Diesel engine.
Based on that response I guess the higher idle regardless of the temperature of the engine is normal?
I also find it troubling having to wait for the RPM to settle back to normal on the warm engine prior to placing it in gear, to avoid causing any damage to the to my vehicle.
Does anyone know if putting it in gear while it’s idling fast is OK? Or if would it cause damage?
Based on that response I guess the higher idle regardless of the temperature of the engine is normal?
I also find it troubling having to wait for the RPM to settle back to normal on the warm engine prior to placing it in gear, to avoid causing any damage to the to my vehicle.
Does anyone know if putting it in gear while it’s idling fast is OK? Or if would it cause damage?
Last edited by swift45; Jan 7, 2022 at 09:24 PM. Reason: Adding questions >
Newbie
Joined: Jun 2022
Posts: 3
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2017 c43
2017 c43 SU
So in getting my annual service done there was an ECM flash that the dealer did.
Now when the car is warm, when starting most of the time it does a high idle run for a similar amount of time it used to do only when doing a cold start.
Anybody else experience this and does this sound right?
Now when the car is warm, when starting most of the time it does a high idle run for a similar amount of time it used to do only when doing a cold start.
Anybody else experience this and does this sound right?
Newbie
Joined: Jun 2022
Posts: 3
Likes: 0
2017 c43
High revs
I just had my 2017 SL550 with 11K miles at the dealership for update. Idle is very similar during warm startups as well as cold start ups. We also own a 2014 E550 with 38K miles that only has the fast idle during cold starts! I asked the dealer to explain the difference, and was told the starting with 2017 the injection system in the 4.7 motor is very similar to a Diesel engine.
Based on that response I guess the higher idle regardless of the temperature of the engine is normal?
I also find it troubling having to wait for the RPM to settle back to normal on the warm engine prior to placing it in gear, to avoid causing any damage to the to my vehicle.
Does anyone know if putting it in gear while it’s idling fast is OK? Or if would it cause damage?
Based on that response I guess the higher idle regardless of the temperature of the engine is normal?
I also find it troubling having to wait for the RPM to settle back to normal on the warm engine prior to placing it in gear, to avoid causing any damage to the to my vehicle.
Does anyone know if putting it in gear while it’s idling fast is OK? Or if would it cause damage?
so is the high revs on warm starts normal now?
MBWorld God!
Joined: Dec 2019
Posts: 32,505
Likes: 6,347
Yes intended behaviour, all our cars that did this update has this behaviour after sitting for more than 20 minutes. All facelift C 43 (MY19+) has it out of the box, I think even all 2019 MBs across the range also does it.
